The short-term effects of exercise on lactate, heart rate, stroke volume, cardiac output and breathing, and how the systems work together to recover.

What this dot point is asking

Edexcel wants you to describe the short-term effects of exercise on lactate, muscle fatigue, heart rate, stroke volume, cardiac output and breathing, and explain how the cardiovascular and respiratory systems work together during exercise and recovery.

Short-term effects on the muscles

Short-term effects on the heart

For example, if heart rate rises from $70$ to $170$ beats per minute and stroke volume from $70$ to $100$ ml, cardiac output rises from $70 \times 70 = 4900$ to $170 \times 100 = 17000$ ml per minute, a large increase in oxygen delivery.

Short-term effects on breathing

Working together to recover

The cardiovascular and respiratory systems work together to allow exercise and recovery. Oxygen is taken into the lungs, transferred to the blood at the alveoli, and transported by the blood to the muscles; carbon dioxide is carried back and breathed out. After exercise, heart rate and breathing stay elevated to take in extra oxygen and carry it to the muscles to break down the lactic acid produced anaerobically. The faster these values return to rest, the fitter the performer, which is why recovery rate is a useful measure of cardiovascular fitness.

Short-term effects on body temperature

These short-term changes are temporary and reverse within minutes to hours of stopping, which is the key difference from long-term effects. Long-term effects, such as a lower resting heart rate or muscle hypertrophy, are permanent adaptations that build up over weeks of training; the short-term effects above happen during, and just after, a single session.